In a wireless communications system including a plurality of base stations with at least some of the base stations using the same air resources, e.g., frequency spectrum, downlink transmission from one base station can interference with downlink transmissions of other, e.g., adjacent base stations using the same frequency spectrum. Downlink traffic channel loading conditions at a particular base station attachment point typically vary over time as a function of a number of factors including: number of users, types of users, types of applications in use, amounts of data to be communicated, error tolerance levels, latency requirements, channel conditions, error rates, an wireless terminals' locations. Varying the transmission power level of a traffic channel segment can influence achievable information data rates to a particular wireless terminal, but also changes the level of interference from the perspective of other wireless terminals attached to a different base station attachment point of another, e.g., adjacent, base station using the same frequency spectrum.
By using a fixed downlink transmission power budget for each base station attachment point overall downlink interference in the system can be controlled. The power associated with different sub-channels within the downlink traffic channel can be varied with the overall downlink power budget being maintained to a fixed level. This approach tends to limit overall interference in the system, but fails to take advantage of different system loading conditions to optimize throughput.
It would be advantageous if a base station were not restrained to a single downlink power budget but could vary its downlink transmission power budget in response to changing loading conditions at its own or adjacent base stations. It would be beneficial if adjacent base stations exchanged loading information thus allowing a base station to make timely decisions regarding downlink transmission power levels. In addition, it would be beneficial if the power budget determinations for a particular base station were performed at the base station, since the base station has readily available pertinent information such as current loading conditions, current channel conditions, user profiles, detected changes, applications in progress, thus facilitating a rapid informed response to changing conditions.